Inhibition of ATP synthase reverse activity restores energy homeostasis in mitochondrial pathologies

Abstract

The maintenance of cellular function relies on the close regulation of adenosine triphosphate (ATP) synthesis and hydrolysis. ATP hydrolysis by mitochondrial ATP Synthase (CV) is induced by loss of proton motive force and inhibited by the mitochondrial protein ATPase inhibitor (ATPIF1). The extent of CV hydrolytic activity and its impact on cellular energetics remains unknown due to the lack of selective hydrolysis inhibitors of CV. We find that CV hydrolytic activity takes place in coupled intact mitochondria and is increased by respiratory chain defects. We identified (+)‐Epicatechin as a selective inhibitor of ATP hydrolysis that binds CV while preventing the binding of ATPIF1. In cells with Complex‐III deficiency, we show that inhibition of CV hydrolytic activity by (+)‐Epichatechin is sufficient to restore ATP content without restoring respiratory function. Inhibition of CV–ATP hydrolysis in a mouse model of Duchenne Muscular Dystrophy is sufficient to improve muscle force without any increase in mitochondrial content. We conclude that the impact of compromised mitochondrial respiration can be lessened using hydrolysis‐selective inhibitors of CV. image In mitochondria, Complex V can rotate forward or reverse to either synthesize or hydrolyze ATP respectively. Here, isolated inhibition of the reverse activity of CV is sufficient to prevent ATP depletion in conditions of impaired respiration. A new assay to quantify ATP hydrolysis by ATP synthase (CV) shows that CV reverse activity occurs in coupled mitochondria. The polyphenol (+)‐Epicatechin is identified as a selective inhibitor of CV reverse activity while leaving synthesis unaffected. In cells with impaired respiratory function (+)-Epicatechin can increase cellular ATP content without restoring respiratory function. Muscle injury in a mouse model of Duchenne Muscular Dystrophy results in an increased CV reverse activity that correlates with the loss of muscle strength. (+)‐Epicatechin decreases ATP hydrolysis and improves muscle force in the Duchenne Muscular Dystrophy mouse model.